Explanation:

- Ratio Conversion: Convert ratios to a common base. Consider salaries of A, B, and C as 3x, 6y, and 4z respectively. Make these ratios comparable by finding a common base through the least common multiple.

- Common Ratio: By comparing ratios, adjust them to a common base of 60 (multiple of 2, 5, and 3). Adjust as: A = 45k, B = 36k, and C = 40k.

- Salary of A and B: Combined salaries: \( 45k + 36k = 81k \).

- Total Salary Calculation: Since A and B's total salary is Rs. 40,500, equate \( 81k \) to 40,500. Solve for k giving, \( k = 500 \).

- Individual salaries: A = \( 45 \times 500 = 22,500\), C = \( 40 \times 500 = 20,000\).

- Percentage Calculation: A's salary is more than C's by: \(\frac{(22,500 - 20,000)}{20,000} \times 100 = 12.5\%\).

- Answer: Option 4: 12.5% is correct.

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